Expendable shaped explosive charge well casing perforating apparatus



2,957,414 Patented Oct. 275, 1960 1 2 7 aluminum, for example, closed at its upper and lower ends by a cable head 12 and a nose plug 13, respectively. 2,957,414 The cable head 12, to which the supporting cable 14 is secured, is preferably made of strong material such as EXPENDABLE SHAPED EXPLOSIVE CHARGE M steel, for example, so as not to be damaged by the ex- WELL CASING PERFORATING APP TUS plosive forces developed in a perforating operation. The

Glen Reid Hodgson, Houston, Tex., assignor, by mesne cable head 12 has a portion 15 of reduced diameter assignments, t -Wh Corporation, Chicago, which is adapted to be snugly received within the upper awfilol'atloh of mlnols end of the tube 11 and which is weakly secured to the o 22 017 latter by one or more shear pins 16, for example, so as Flled Nov 1952 Set Q 3 to facilitate separation of the two when the perforating 2 Claims. (Cl. 10220) apparatus is fired. Packing means such as one or more O-rings 17 may be disposed in an annular groove 18 formed in the cable head portion 15, to insure Water- The present invention relates to apparatus utilizing tightness.

shaped explosive charge means in expendable carrier Similarly, the nose plug 13 has a portion 19 of remeans which is adapted to be lowered into a well on a duced diameter which is snugly received within the lower supporting cable or other suspension means to perforate end of the tube 11 and secured thereto by one or more the well casing, for example. More specifically, it has screws 20, for example, one or more O-rings 21 being to do with novel means for completely separating the provided in an annular groove 22 in the nose plug portion expendable carrier means from the suspension means 19 to insure a watertight joint. upon detonation of the explosive charge means. Within the'tube 11 are a plurality of longitudinally In the completion of oil and gas wells, it has become spaced apart shaped explosive charge devices 23 which common practice to perforate the well casing to bring 'may be mechanically coupled together by cooperating a well into production after the small diameter tubing coupling means 24 and 25 with their longitudinal axes at has been set and the production equipment h b inoblique angles to the longitudinal axis of the tube 11, all stalled at the surface. This has been made possible by as explained in the aforementioned Robertson applicathe recent development of highly effective perforating tiOH- T P iV charges in the devices 23 are adaP apparatus hi h i ll enough t pass through th to be detonated by a Pn'macord fuse 26 which is threaded Well tubing. As disclosed in the copending application gh p n gs 27 at the rear of the explosive charge Serial No. 209,598, filed February 6, 1951 by H s devices 23, the lower end of the fuse 26 being mechan- Robertson, for Apparatus for Perforating Well Casing ically coupled to an electric blasting cap 28. One termiand the Like, now US. Patent No. 2,853,944, issued nel of the blasting p 28 y be grounded o e no e September 30, 1958, such apparatus comprises one or P 13 at 29 and its Other terminal y be connected more shaped explosive charge devices mounted in exby a conductor 30 to a terminal 31 which connects to a pendable carrier means adapted to be lowered into a well Conductor 32 in the Supporting cable 14 eXtehdiIlg to on suspension means. Upon detonation of the charges, the Surface the The PP end Of the 11- the carrier means is destroyed and only the suspension ductof 32 is connected in Series With a firing Switch means is brought out of the well. Complete destruction 3 Theostat 34 for Controlling current intensity, and a of the carrier means is desirable since if deformed or Source Of electrical energy 35, the other end of which only partially destroyed portions of the carrier remain is gTOunded at attached to the suspension means, it may be diflicult to In acchrdahce with the invention, the pp end of the withdraw the latter through the well tubing Primacord fuse 26 is wound in the form of a helical coil I i an bj f h invention, th r f to provide 26a of several turns having substantially the same outer well casing perforating apparatus of the above character dlametel' as the inside diameter of the tube y Suit- Which includes means for positively severing the carrier able means Such as friction h for 1 means from the suspension means therefor without leavample, being used to hold it in h p A lar m m r 1 ing deformed carrier portions on the latter which might of Substantially the Same er d ameter as the inner k i difficuh to withdraw the suspension means diameter of the coil 26a is then inserted within the coil through the well tubing upon completion f a pe fo t 26a and the coil 26a and member 37 are inserted in the i operation upper end of the tube 11 as shown in the figure.

This is accomplished, according to the invention, by In Operation, the pp s 10 is lowered into a well placing explosive charge means in juxtaposition to the and brought to Test at the level therein Where a P carrier means near the place where the latter is secured fel'atlhg Operation is to b made. The switch 33 is then to h Suspension means U detonation f h closed, detonating the explosive charges in the devices 23 forating explosive charges, the explosive charge means and Perforating the Surmhhdhlg earth ti s S is detonated to separate the carrier means cleanly from muhaheously, the detonation 0f the Portion 0f the f the suspension means. In a preferred embodiment, the 26 pp around the member Completely destroys explosive means comprises a portion of the detonating the pp end of the tube 11 and leaves 110 Parts thereof fuse for the perforating explosive charges, which may be attached to the cable head 12 so that the latter can readily wrapped around a suitable member in close proximity to be Withdrawn through the narrow diameter tubing in the the upper end of the carrier means. By virtue of this well. The member 37 aids in directing the forces deconstruction, the separation of the carrier means from its veloped upon deonation of the fuse 26 outwardly against L suspension means may be effected in a simple yet highly the upper end of the tube 11.

effective manner. The invention thus provides novel means for insuring For a better understanding of the invention, reference the complete separation of the cable head from the rest is made to the following detailed description of a typical of the apparatus upon detonation of the explosive charges embodiment, taken in conjunction with the single accomtherein. By employing weak securing means to secure panying figure. the cable head to the carrier means and by detonating a t, In the figure, the shaped charge perforating apparatus coiled portion of the detonating fuse for the perforating 10 may comprise a hollow, imperforate, pressure resilient charges in close Proximity to the Carrier means a t e tube 11 made of any suitable frangible material such as place where it is connected to the cable head, the carrier means may be cleanly separated from the cable head in a simple and effective manner.

It will be understood that the representative embodiment described herein is susceptible of modification within the spirit of the invention. For example, the tubular member 37 might be eliminated. Also, the return circuit to the perforator apparatus in the well may be through the earth or through the metal armor of the cable 14. Similarly, the helical coil of Primacord fuse may be replaced by an explosive charge of adequate shape, for example a circular ring, adapted to be ignited by the Primacord fuse 26. Further, the apparatus may be used in conjunction with a casing collar locator of the type shown in Pagan Patent No. 2,558,427 located in an extension of cable head (not shown). The single 'embodiment disclosed, therefore, is to be regarded merely as illustrative of the invention and not as limiting the scope of the appended claims.

I claim:

1. In apparatus for perforating well casing and the like, the combintion of an elongated expendable, relatively thin-walled tube providing a hollow interior of a size to receive shaped explosive devices, said tube having a closure member for the lower end thereof, a non-expendable head member weakly secured to the upper end of said tube and forming a closure therefor, suspension means connected to said head member for suspending the apparatus in a well, a plurality of longitudinally spaced apart shaped explosive devices disposed in the hollow interior of said tube, a rigid member mounted in the upper end of said tube, said member being spaced from the inside wall of said tube to provide with the latter an annular space, a flexible detonating fuse having portions disposed adjacent the rear ends of said explosive devices and having an end portion disposed circumferentially in the space between said rigid member and the inside wall of said tube in close proximity to said'inside wall, said fuse end portion being capable of severing said tube from said head member, and means for initiating detonation of said fuse from the surface of the earth, whereby the body of said expendable tube and the contents thereof will be destroyed upon detonation of said charges and the tube will be cleanly separated from the head member.

2. In apparatus for perforating well casing and the like, the combination of an elongated expendable, relatively thin-walled tube providing a hollow interior of a size to receive shaped explosive devices, said tube having a closure member for the lower end thereof, a nonpendable head member having a portion extending into the upper end of said tube in fluid-tight telescopic relation thereto, means including a shearable element weakly securing said tube to said extending portion of said head member, said head member forming a closure for said tube, suspension means connected to said head member for suspending the apparatus in a well, a plurality of longitudinally spaced apart explosive devices disposed in the hollow interior of said tube, a rigid member mounted in the upper end of said tube, said member being spaced from the inside wall of said tube to provide with the latter an annular space, a flexible detonating fuse having portions adjacent the rear ends of said explosive devices and having an end portion disposed circumferentially in the space between said rigid member and the inside wall of said tube in close proximity to said inside wall, said fuse end portion being capable of severing said tube from said head member, and means for initiating detonation of said fuse from the surface of the earth, whereby the body of said expendable tube and the contents thereof will be destroyed upon detonation of said charges and the tube will be cleanly separated from the head member.

References Cited in the file of this patent UNITED STATES PATENTS 855,224 Broadwater May 28, 1907 2,494,256 Muskat et al Jan. 10, 1950 2,543,814 Thompson et a1. Mar. 6, 1951 2,614,804 Carlisle Oct. 21, 1952 2,621,895 Toelke Dec. 16, 1952 2,649,046 Davis Aug. 18, 1953 2,733,657 Bryant et al. Feb. 7, 1956 2,749,840 Babcock June 12, 1956 UNITED STATES PATENT OFFICE CERTIFICATE OF 'CQRRECTION Patent N0a 2,- 957 4l4 October 25 1960 Glen Reid Hodgson It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1 line 71 for "resilient" read resistant w Signed and sealed this 25th day of April 1961a (SEAL) Attest:

ERNEST Wu SWIDER DAVID L LADD Attesting Ofiicer Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0a 2 957 414 October 25 1960 Glen Reid Hodgson It is hereby certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1 line 71 for "resilient" read resistant e Signed and sealed this 25th day of April 1961 (SEAL) Attest:

ERNEST we s wiDER DAVID LADD Atiesting Ofiicer Commissioner of Patents 

